It appears the Mets' negotiations with the agents for Johan Santana won't be over quickly.

Sources familiar with those discussions said Thursday that while the talks may not go right to Friday's 5 p.m. ET deadline, the two sides were still far enough apart that it was unlikely any deal could be reached before Friday morning at the earliest.

The sources also left open the possibility that the talks could collapse without an agreement, though the odds of that appear remote.

Santana's agents, Peter and Ed Greenberg, are believed to be looking for a six-year extension in the range of $150 million -- a figure that would include an upfront payment that would boost Santana's 2008 salary ($13.25 million) to beyond $20 million.

The Mets, not surprisingly, differ on the dollars. But the biggest obstacle appears to be the length of the deal.

Indications are that the Mets want to limit the guaranteed portion of the extension to five years, not including Santana's current contract, which expires after 2008. So if Santana's side is adamant that the deal extend beyond 2013, it's believed the Mets would insist that the back end of the contract not be guaranteed, but could include at least one vesting option year.

In the meantime, there are signs that the Mets continue to express interest in free-agent pitcher Kyle Lohse. Lohse was viewed, essentially, as the Mets' backup plan in case they weren't able to trade for Santana. But when one baseball man who had spoken with Mets GM Omar Minaya was asked if the club could end up with both Santana and Lohse, the reply was: "Absolutely."